She added that after suggesting potpourri for the toilet, McConaghie arrived at work one day with some stored inside a square pot that was placed on the toilet. Later, another pot arrived and was put in the same place.

One was round and the other square, but both had holes in their sides. One was placed six inches from the corner, directly facing the toilet, while the other was behind the door. However, when the door was shut it too faced the toilet.

The witness explained that when she used the facilities, she would push the pot back into the corner because she thought it looked a bit tidier. But the pot kept getting moved back to its original position.

At lunchtime on September 12, 2012, she asked her co-worker if she had been moving the pot, but she said no. The witness then told her what she had been doing for a number of weeks - that she had been deliberately moving the pot into the corner, only for someone to deliberately move it back out again.

The woman then decided to bring some more potpourri to the office, empty the two pots and replace the contents.

Afterwards, she claimed she went back to work and brought the pots down to the main office. When she and her colleague were emptying them, a device fell out. And when it was pressed, a red light switched on, shocking both women.

The witness explained that she and her co-worker refilled the pots and brought them back up to the toilet, passing the office of the defendant, who was on the phone, but told the person he was speaking to: "I have to go."

She added that McConaghie seemed anxious to get into the bathroom, after which he walked down to the main office.

The woman then went to her parents' house to put the device in a laptop but, because she had forgotten her keys, she called back at the office.

When she watched the footage on the device, the only thing she saw was by McConaghie placing it inside the pot.

The witness also told of meeting with Upper Bann MP Mr Simpson, and of explaining the sequence of events to him. She believed they could maybe just talk about the issue with people in the office, but Mr Simpson said that was not an option because he had a duty of care to his staff.

The witness said she later met with Mr Simpson, who said McConaghie had handed in his resignation within 24 hours of the camera being discovered.

Asked about the footage taken, she said she felt "devastated" and that it was "very embarrassing", because she thought so much of McConaghie.

The public prosecutor asked her if she had been aware of the device or given her consent. "Absolutely not," she replied.

After the camera was found Mr Simpson decided it had to be handed over to the PSNI.

The politician, who also gave evidence in court, told of speaking to the first witness about finding the recording device. He said that afterwards he went back to his office, put it in a plastic bag in a drawer and locked it.

He added that he asked the witness to meet him again. At the later meeting they played the footage on a laptop. After 20 or 30 seconds Mr Simpson turned it off and said he needed to inform the PSNI.

The politician said the accused rang him and they arranged to meet, at which point McConaghie handed him an envelope containing his letter of resignation.

The MP also told of meeting with the PSNI and handing over the camera, saying that the issue was something that had "come out of the blue".

The court heard that of three CDs seized by police, two contained video files and the third 230 images.

A detective sergeant who examined the camera said there were a total of 216,373 images and 15 video files.